1. Field of the Invention
The invention relates to an optical apparatus which is provided with a laser and optical means for expanding a laser beam output in a plane. In particular, the invention relates to an optical apparatus which also includes an optical element which divides the laser beam into several beams of preferably identical intensity. The optical apparatus is particularly suited for use in a ballistics device.
2. Description of the Prior Art
In the prior art apparatus for expanding a coherent laser beam output typically comprise a cylindrical lens positioned along the optical axis of the laser beam. This arrangement in the prior art has the disadvantage of a decreasing intensity of the laser beam with increasing angle of divergence of the laser beam from its optical axis. This effect is due to the Gaussian distribution of intensity of the laser beam over its cross-section, symmetrical about the optical axis of the laser. Such a decrease in intensity away from the optical axis is undesirable in many laser applications, particularly in ballistics devices used to optically measure characteristics of moving projectiles.